Just when you thought the prime-time body count couldn’t get any higher comes a fourth “Law & Order” show – “Trial by Jury” on Friday nights.

That’s for those who aren’t getting enough mob hits, sniper victims and beheadings on the other three nights of “Law & Order.”

Not to mention the rotting stiffs that open every episode of TV’s hottest franchise: “CSI,” “CSI: NY,” “CSI: Miami” and possibly someday “CSI: New Orleans.”

It’s crime-time television at its bloodiest – and people can’t get enough of it.

Some 59.3 million viewers a week tune into the three “CSI”series, while a total of 57million watch the four “Law & Order” shows. And millions more get their murder fix on popular plug ’em and dump ’em shows including “The Shield,” “Cold Case,” “Without A Trace,” “Numbers,” “Blind Justice,” “Medium” and “NCIS.”

The glut of bodies shows there’s plenty of life in the old TV murder mystery, even as the sitcom is gasping for breath. “Since 9/11, there’s been a hunger for shows where justice is being served,” says Marc Berman, senior television writer at Mediaweek. “Crime shows have become a new kind of comfort food.”

Then that makes “CSI” and “Law & Order” the McDonald’s and Burger King of the genre. In fact, the ratings battle between these two crime-solving franchises is as big a bloodbath as anything on screen.

It all started five years ago, when “Law & Order,” television’s longest-running prime-time drama, was upstaged by the younger, hipper “CSI,” a monster hit out of the gate in 2000.

The “CSI” style of computerized graphics, sexy lighting and zoom shots of bullet holes seemed to have a buzz of energy lacking in the linear, well-written police interrogations and courtroom scenes on “Law & Order.”

That meant “Law & Order” creator Dick Wolf, who had already launched the successful “Law & Order: Special Victims Unit” in 1999, had to play catch-up.

He introduced “Law & Order: Criminal Intent” a year later, only to watch as the “CSI” team took its red-hot formula to another flashy locale (tropical Florida) and threw a proven star (David Caruso) into the mix for “CSI: Miami” in 2002.

Then in 2004, came “CSI: NY” on Wednesday night, a direct challenge to Wolf’s flagship show. It handily beat “Law & Order” in its premiere.

Since then, “CSI” and “Law & Order” have been running neck and neck, and the battle between TV’s biggest brand and its hottest dramatic franchise is far from over.

While “Law & Order” looks at the criminal justice system from the perspective of cops and prosecutors, “Trial by Jury,” starring theater diva Bebe Neuwirth (“Chicago”), focuses on defense attorneys, defendants and jurors.

The series had hoped to get a boost from Neuwirth’s co-star, Jerry Orbach, the enormously charismatic New York actor who became a household name as “Law & Order” detective Lennie Briscoe. But his death last December left the burden of “Trial by Jury” squarely on Neuwirth’s shoulders.

Unproven as a series lead, she is best-known to TV viewers as Lilith, the haughty ex-wife of Frasier Crane on “Frasier”; her last TV series was the quickly forgotten 2000 Dick Wolf newspaper drama “Deadline.”

While “Trial by Jury” debuted with a reasonable 17.8 rating, its future without Orbach – whose final appearance on the show airs Friday – seems less than starry.

Will the “CSI” team tries to best “Law & Order” again by adding a fourth procedural to the CBS lineup?

Sources at the network would not comment, but there have been rumors that the next “CSI” could set up shop in New Orleans.

But Marc Berman thinks “Law & Order” went one trial too far in adding a fourth show and “CSI” should not make the same mistake.

” ‘Law & Order’ has peaked,” he says. “Four hours is enough already.”

And Variety columnist Brian Lowry says some of these shows might be bound for the morgue.

” ‘Trial by Jury’ didn’t do that well, and ‘CSI: NY’ isn’t doing as well as its predecessors. It might be that nobody knew what the saturation point was for the crime shows,” he says. “Maybe we’re seeing the cusp.”

Discursive cops-and-lawyers drama that takes a criminal case from arrest to trial. Big on speeches. … STYLE … High-tech drama where crimes are solved through forensic examination of evidence, resulting in arrest. Big on science.

You like your crime stories with a neat beginning, middle and end. You like to hear lawyers pontificate about motives and justice. You are a frustrated juror. … WHICH ONE ARE YOU? … Knowing who committed the crime is not enough – you want to see the weapons, their points of entry, the ruptured organs, etc. You are a frustrated coroner.